Date mapping

Different RSS and Atom versions define different date elements at feed and entry level. Some of them also define syndication informations indicating when (and when not) and how often to fetch feeds for updates. There is not always a possible mapping or conversion of this information when going from one format to another.

In ROME we've taken a simplistic approach, as this is still subject of debate (How About a Date and Date Survey).

When handling feeds at WireFeed level (Channel or Feed) it is possible to access all the date elements and syndication informations available in the feed.

When handling feeds at SyndFeed level, there is only the publishedDate date element available on SyndFeed and SyndEntry. In addition, it is possible to use the Syndication module.

The mapping of the date elements from different feed formats to SyndFeed is as follows.

RSS 0.90

RSS 0.90 does not define date elements.

There is no mapping to SyndFeed and SyndEntry date properties.

RSS 0.91 and 0.92

RSS 0.91 and 0.92 define pubDate and lastBuildDate at feed level.

The feed pubDate element is mapped to the SyndFeed publishedDate property. The lastBuildDate element is lost.

RSS 0.93, 0.94 and 2.0

RSS 0.93, 0.94 and 2.0 define pubDate and lastBuildDate at feed level. They also define pubDate and expirationDate at item level.

The feed pubDate element is mapped to the SyndFeed publishedDate property. The lastBuildDate element is lost.

The item pubDate element is mapped to the SyndEntry publishedDate property. The expirationDate element is lost.

RSS 1.0

RSS 1.0 uses DC Module data at feed and item level to indicate date information about the feed and the items.

SyndFeed and SyndEntry use the DC Module date element for the publishedDate property.

Atom 0.3

Atom 0.3 defines a modified element at feed level and the modified, created and issued elements at entry level.

The feed modified element is mapped to the SyndFeed publishedDate property.

The item modified element is mapped to the SyndEntry publishedDate property. The entry elements created and issued are lost.

Atom 1.0

Atom 1.0 defines an updated element at the feed level, which ROME maps to the SyndFeed publishedDate property.

Atom 1.0 defines updated and published elements at the entry level, which ROME maps to SyndEntry updatedDate and publishedDate respectively.